Melt-Spun Magnets

Abstract

The discovery of high performance melt-spun Nd-Fe-B magnets ushered in a new era in permanent magnets. Since then, melt-spinning has proven to be a powerful and versatile technique for magnetic hardening, and a commercially viable alternative to conventional powder metallurgy (sintering) processing. Although most often viewed as a means of making amorphous metals, its success in fabricating permanent magnets depends instead on its ability to produce nanocrystalline material: crystalline compounds with submicron grain sizes. The wide variety of materials amenable to melt-spinning makes it an excellent research tool for exploring the potential as permanent magnets of compounds having favorable intrinsic magnetic properties, and evaluating the effects of compositional variations and additives on their hard magnetic properties. As a non-equilibrium process it is capable of fabricating magnetically hard metastable compounds which are difficult or impossible to make by more conventional means. Most recently, melt-spinning has been used to magnetically harden Sm-Fe-V and Sm-Fe-Ti alloys.